Hitherto, there has been known an AC generator for a vehicle including a frame configured to house a rotator and a stator, and a rectifier fixed to an outer end surface of the frame. The rectifier includes a large-diameter fin, which is fastened to a plurality of fastening and fixing portions circumferentially spaced from one another and protruding from the frame, and has rectifier elements arranged thereon. The frame has protruding portions in contact with the large-diameter fin protruding from the frame so as to suppress vibration of the large-diameter fin. The protruding portions are each located circumferentially in the middle between two fastening and fixing portions (see, for example, Patent Literature 1).
Further, to enhance a cooling performance of a cooling fin by enlarging a heat dissipation surface of the cooling fin, there has been hitherto known an AC generator for a vehicle including a rectifier having a plurality of slits formed along a ventilation direction in an outer peripheral portion of the cooling fin, to which a plurality of rectifier elements are mounted. The cooling fin is fixed via a plurality of rivets to a terminal block, which is configured to electrically connect an output line from a stator to each of the rectifier elements. The rivets are located on an inner side with respect to the outer peripheral portion of the cooling fin (see, for example, Patent Literature 2).